The present invention relates generally to handling nuclear fuel pellets and more particularly to a system for loading newly-made (green) nuclear fuel pellets into a sintering boat from a pellet press.
An operational step in the nuclear fuel fabrication process is the loading of green nuclear fuel pellets, which have been ejected from the pellet press, into sintering containers, "boats", in preparation for high-temperature firing of the pellets in a sintering furnace. This operation requires careful handling of the pellets, because the pellets at this time are fragile and susceptible to damage.
It is known in the prior art to load nuclear fuel pellets into a sintering boat by a gravity discharge from the pellet press down a chute into the boat. This method has the disadvantage of allowing pellet to pellet impact and has considerable potential for pellet damage. In addition, random orientation of the pellets in each sintering boat reduces the loading density and therefore reduces the high-temperature firing production capacity.
A mechanized boat loader also is known, in the prior art, which includes a pick and place mechanism with mechanical blades or jaws to pick up a single row of nuclear fuel pellets at a time and to transfer that row into the sintering boat. If further is known to utilize a boat loader with a vacuum transfer head which lowers onto an array of nuclear fuel pellets, applies a vacuum to lift the pellets, and transfers the array to load a complete layer of pellets into the sintering boat at one time. These two methods have the disadvantage of requiring frequent attention to maintain the pick and place mechanisms operational.
U.S. Pat. No. 4,332,120 discloses apparatus for loading nuclear fuel pellets, via gravity, into a container supported by a platform which lowers under increasing pellet weight thereon.
U.S. Pat. No. 3,027,020 discloses a rotating drum with longitudinally aligned circumferential channels to load rows of cans onto a conveyor.
What is needed is a relatively maintenance free sintering boat loader which achieves high loading density without nuclear fuel pellet damage.